/[svn]/linuxsampler/trunk/src/engines/common/LFOPulse.h
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Annotation of /linuxsampler/trunk/src/engines/common/LFOPulse.h

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Revision 2223 - (hide annotations) (download) (as text)
Fri Jul 29 13:39:58 2011 UTC (12 years, 8 months ago) by iliev
Original Path: linuxsampler/trunk/src/engines/common/PulseLFO.h
File MIME type: text/x-c++hdr
File size: 5195 byte(s)
* implemented sine LFO, pulse LFO and saw LFO
* sfz engine: implemented opcode lfoN_wave

1 iliev 2223 /***************************************************************************
2     * *
3     * Copyright (C) 2005 Christian Schoenebeck *
4     * Copyright (C) 2011 Christian Schoenebeck and Grigor Iliev *
5     * *
6     * This library is free software; you can redistribute it and/or modify *
7     * it under the terms of the GNU General Public License as published by *
8     * the Free Software Foundation; either version 2 of the License, or *
9     * (at your option) any later version. *
10     * *
11     * This library is distributed in the hope that it will be useful, *
12     * but WITHOUT ANY WARRANTY; without even the implied warranty of *
13     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
14     * GNU General Public License for more details. *
15     * *
16     * You should have received a copy of the GNU General Public License *
17     * along with this library; if not, write to the Free Software *
18     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
19     * MA 02111-1307 USA *
20     ***************************************************************************/
21    
22     #ifndef __LS_PULSELFO_H__
23     #define __LS_PULSELFO_H__
24    
25     #include "LFOBase.h"
26    
27     namespace LinuxSampler {
28    
29     /** @brief Pulse LFO (int math implementation)
30     *
31     * This is a pulse Low Frequency Oscillator which uses pure integer
32     * math (without branches) to synthesize the pulse wave.
33     */
34     template<range_type_t RANGE, int WIDTH /* in permilles */>
35     class PulseLFO : public LFOBase<RANGE> {
36     public:
37    
38     /**
39     * Constructor
40     *
41     * @param Max - maximum value of the output levels
42     */
43     PulseLFO(float Max) : LFOBase<RANGE>::LFOBase(Max) {
44     }
45    
46     /**
47     * Calculates exactly one sample point of the LFO wave.
48     *
49     * @returns next LFO level
50     */
51     inline float render() {
52     uiLevel += c;
53     if (RANGE == range_unsigned)
54     return uiLevel <= width ? normalizer : 0;
55     else /* signed range */
56     return uiLevel <= width ? normalizer : -normalizer;
57     }
58    
59     /**
60     * Update LFO depth with a new external controller value.
61     *
62     * @param ExtControlValue - new external controller value
63     */
64     inline void update(const uint16_t& ExtControlValue) {
65     const float max = this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff;
66     normalizer = max;
67     }
68    
69     /**
70     * Will be called by the voice when the key / voice was triggered.
71     *
72     * @param Frequency - frequency of the oscillator in Hz
73     * @param InternalDepth - firm, internal oscillator amplitude
74     * @param ExtControlDepth - defines how strong the external MIDI
75     * controller has influence on the
76     * oscillator amplitude
77     * @param FlipPhase - inverts the oscillator wave against
78     * a horizontal axis
79     * @param SampleRate - current sample rate of the engines
80     * audio output signal
81     * @param PulseWidth - the pulse width in percents
82     */
83     void trigger(float Frequency, uint16_t InternalDepth, uint16_t ExtControlDepth, float PulseWidth, unsigned int SampleRate) {
84     this->InternalDepth = (InternalDepth / 1200.0f) * this->Max;
85     this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max;
86    
87     const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
88     const float r = Frequency / (float) SampleRate; // frequency alteration quotient
89     c = (int) (intLimit * r);
90     width = (PulseWidth / 100.0) * intLimit;
91    
92     uiLevel = 0;
93     }
94    
95     virtual void trigger(float Frequency, start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) {
96     trigger(Frequency, InternalDepth, ExtControlDepth, WIDTH / 10.0f, SampleRate);
97     }
98    
99     protected:
100     unsigned int uiLevel;
101     unsigned int width;
102     int c;
103     float normalizer;
104     };
105    
106     template<range_type_t RANGE>
107     class SquareLFO : public PulseLFO<RANGE, 500> {
108     public:
109     SquareLFO(float Max) : PulseLFO<RANGE, 500>::PulseLFO(Max) { }
110     };
111    
112     } // namespace LinuxSampler
113    
114     #endif // __LS_PULSELFO_H__

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